Move frame_type member from RtpDepacketizer::ParsedPayload to RTPVideoHeader

The latter is also a member of the former. This cleanup is also
a preparation for dropping WebRtcRTPHeader::frameType (or deleting
WebRtcRTPHeader right away), now that it's a video-specific member.


Tbr: kwiberg@webrtc.org # Comment change in modules/include/
Bug: None
Change-Id: I5c1f3f981f0d750713fc9b9b145278150fe32b5d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/133024
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27740}

modules/video_coding/frame_buffer.cc

@@ -94,7 +94,7 @@ VCMFrameBufferEnum VCMFrameBuffer::InsertPacket(
     // We only take the ntp timestamp of the first packet of a frame.
     ntp_time_ms_ = packet.ntp_time_ms_;
     _codec = packet.codec();
-    if (packet.frameType != VideoFrameType::kEmptyFrame) {
+    if (packet.video_header.frame_type != VideoFrameType::kEmptyFrame) {
       // first media packet
       SetState(kStateIncomplete);
     }